Most African-Americans who are likely to or who are committing crimes are already registered.

They are young to middle-aged males. Most of them are "registered" in the criminal justice system by the time they are teenagers.

In fact, with government records of all sorts--births, school records, medical records, criminal justice system records, crime statistics, poverty statistics, etc.--these people are the most "registered people" in history. The question then remains, why is nothing done with this information to ameliorate the problem?